The present invention relates to a fluid recovery system for an automatic transmission unit.
Automatic transmission units for vehicles, in particular automobile vehicles, are known in which the clutch and the gear change of the vehicle are associated with actuators used respectively for the opening/closing of the clutch and/or the selection and engagement/disengagement of the gears.
The above-mentioned actuators are generally of hydraulic or electro-hydraulic type and are supplied by means of a hydraulic pump receiving an operating fluid (normally oil) from a hydraulic circuit which is coupled to the actuators and is adapted to provide these actuators with the pressurised operating fluid so that they can operate.
During the normal operation of automatic transmission units, there may be leakages of operating fluid from the actuators because the gaskets present in these actuators are not fully leak-tight; this lack of leak-tightness may in particular be caused by damage to or wear of the gaskets.
This situation may cause fluid to escape from the hydraulic circuit causing a possible malfunction of the automatic transmission unit and pollution of the external environment; when the quantity of operating fluid escaping from the circuit as a result of leakages is a substantial proportion, for instance 20-30%, of the volume of the operating fluid in the hydraulic circuit, operating anomalies may occur as a result, for instance, of the intake of air or other gases by the pump.
A known solution is to provide the hydraulic actuators with high quality gaskets so as to reduce fluid leakages to predetermined values.
This solution has the drawback that it is particularly costly and does not make it possible to recover the fluid that has leaked.
The object of the present invention is therefore to provide an operating fluid recovery system for a transmission unit which is free from the above-mentioned drawbacks.
The present invention relates to an operating fluid recovery system for a transmission unit as described in claim 1.